The present invention relates to a plasma processing apparatus or plasma processing method for applying a processing such as etching to a sample such as semiconductor wafer by taking advantage of plasma. More particularly, it relates to a plasma processing apparatus or plasma processing method for processing a sample while supplying an electric field into a vacuum container.
In accompaniment with the reduction of the pattern sizes of semiconductor devices, in a plasma processing process of a semiconductor fabrication apparatus, the minimum particulate size which becomes target of particulate reduction is also decreased. Simultaneously, it has also become absolutely necessary to reduce the particulate number. In such a plasma processing apparatus, conventionally, when the particulates increase due to an accumulation of deposited substances caused by repetition of the productions, it has been carried out to clean the apparatus by opening the apparatus into the atmosphere.
Also, in such a plasma processing apparatus, a process referred to as “plasma cleaning” is carried out. In this plasma cleaning, the reaction products deposited inside a processing chamber are removed by the plasma processing. As the plasma cleaning, various processes are carried out, such as a case where the plasma cleaning is carried out between lots of a wafer and a case where the plasma cleaning is carried out on each wafer-processing basis.
Meanwhile, there have been known the following methods: A method of suppressing particulate occurrence by controlling the manner of plasma generation as is disclosed in JP-A-2005-116821, a method of removing particulates by loading factors such as electromagnetic waves, sound waves, and mechanical vibration within the plasma as is disclosed in Japanese Patent No. 2741713 (corresponding to U.S. Pat. No. 5,367,139 etc.), and a method of causing microscopic particles to depart from a stage component member by applying a voltage to a wafer on-board stage, and after that, ejecting the microscopic particles through introduction of a gas as is disclosed in JP-A-2005-101539 (corresponding to U.S. Patent Publication No. 2005/082000).